package edu.stanford.nlp.trees;
import edu.stanford.nlp.util.logging.Redwood;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.io.Serializable;
import java.io.StringReader;
import java.io.StringWriter;
import java.util.*;
import java.util.function.Predicate;
import edu.stanford.nlp.ling.CoreLabel;
import edu.stanford.nlp.ling.HasIndex;
import edu.stanford.nlp.ling.HasTag;
import edu.stanford.nlp.ling.HasWord;
import edu.stanford.nlp.ling.Label;
import edu.stanford.nlp.ling.LabelFactory;
import edu.stanford.nlp.ling.LabeledWord;
import edu.stanford.nlp.ling.SentenceUtils;
import edu.stanford.nlp.ling.TaggedWord;
import edu.stanford.nlp.ling.Word;
import edu.stanford.nlp.ling.CoreAnnotations;
import edu.stanford.nlp.util.*;
/**
* The abstract class <code>Tree</code> is used to collect all of the
* tree types, and acts as a generic extensible type. This is the
* standard implementation of inheritance-based polymorphism.
* All <code>Tree</code> objects support accessors for their children (a
* <code>Tree[]</code>), their label (a <code>Label</code>), and their
* score (a <code>double</code>). However, different concrete
* implementations may or may not include the latter two, in which
* case a default value is returned. The class Tree defines no data
* fields. The two abstract methods that must be implemented are:
* <code>children()</code>, and <code>treeFactory()</code>. Notes
* that <code>setChildren(Tree[])</code> is now an optional
* operation, whereas it was previously required to be
* implemented. There is now support for finding the parent of a
* tree. This may be done by search from a tree root, or via a
* directly stored parent. The <code>Tree</code> class now
* implements the <code>Collection</code> interface: in terms of
* this, each <i>node</i> of the tree is an element of the
* collection; hence one can explore the tree by using the methods of
* this interface. A <code>Tree</code> is regarded as a read-only
* <code>Collection</code> (even though the <code>Tree</code> class
* has various methods that modify trees). Moreover, the
* implementation is <i>not</i> thread-safe: no attempt is made to
* detect and report concurrent modifications.
*
* @author Christopher Manning
* @author Dan Klein
* @author Sarah Spikes (sdspikes@cs.stanford.edu) - filled in types
*/
public abstract class Tree extends AbstractCollection<Tree> implements Label, Labeled, Scored, Serializable {
/** A logger for this class */
private static Redwood.RedwoodChannels log = Redwood.channels(Tree.class);
private static final long serialVersionUID = 5441849457648722744L;
/**
* A leaf node should have a zero-length array for its
* children. For efficiency, classes can use this array as a
* return value for children() for leaf nodes if desired.
* This can also be used elsewhere when you want an empty Tree array.
*/
public static final Tree[] EMPTY_TREE_ARRAY = new Tree[0];
public Tree() {
}
/**
* Says whether a node is a leaf. Can be used on an arbitrary
* <code>Tree</code>. Being a leaf is defined as having no
* children. This must be implemented as returning a zero-length
* Tree[] array for children().
*
* @return true if this object is a leaf
*/
public boolean isLeaf() {
return numChildren() == 0;
}
/**
* Says how many children a tree node has in its local tree.
* Can be used on an arbitrary <code>Tree</code>. Being a leaf is defined
* as having no children.
*
* @return The number of direct children of the tree node
*/
public int numChildren() {
return children().length;
}
/**
* Says whether the current node has only one child.
* Can be used on an arbitrary <code>Tree</code>.
*
* @return Whether the node heads a unary rewrite
*/
public boolean isUnaryRewrite() {
return numChildren() == 1;
}
/**
* Return whether this node is a preterminal or not. A preterminal is
* defined to be a node with one child which is itself a leaf.
*
* @return true if the node is a preterminal; false otherwise
*/
public boolean isPreTerminal() {
Tree[] kids = children();
return (kids.length == 1) && (kids[0].isLeaf());
}
/**
* Return whether all the children of this node are preterminals or not.
* A preterminal is
* defined to be a node with one child which is itself a leaf.
* Considered false if the node has no children
*
* @return true if the node is a prepreterminal; false otherwise
*/
public boolean isPrePreTerminal() {
Tree[] kids = children();
if (kids.length == 0) {
return false;
}
for (Tree kid : kids) {
if ( ! kid.isPreTerminal()) {
return false;
}
}
return true;
}
/**
* Return whether this node is a phrasal node or not. A phrasal node
* is defined to be a node which is not a leaf or a preterminal.
* Worded positively, this means that it must have two or more children,
* or one child that is not a leaf.
*
* @return <code>true</code> if the node is phrasal;
* <code>false</code> otherwise
*/
public boolean isPhrasal() {
Tree[] kids = children();
return !(kids == null || kids.length == 0 || (kids.length == 1 && kids[0].isLeaf()));
}
/**
* Implements equality for Tree's. Two Tree objects are equal if they
* have equal {@link #value}s, the same number of children, and their children
* are pairwise equal.
*
* @param o The object to compare with
* @return Whether two things are equal
*/
@Override
public boolean equals(Object o) {
if (o == this) {
return true;
}
if (!(o instanceof Tree)) {
return false;
}
Tree t = (Tree) o;
String value1 = this.value();
String value2 = t.value();
if (value1 != null || value2 != null) {
if (value1 == null || value2 == null || !value1.equals(value2)) {
return false;
}
}
Tree[] myKids = children();
Tree[] theirKids = t.children();
//if((myKids == null && (theirKids == null || theirKids.length != 0)) || (theirKids == null && myKids.length != 0) || (myKids.length != theirKids.length)){
if (myKids.length != theirKids.length) {
return false;
}
for (int i = 0; i < myKids.length; i++) {
if (!myKids[i].equals(theirKids[i])) {
return false;
}
}
return true;
}
/**
* Implements a hashCode for Tree's. Two trees should have the same
* hashcode if they are equal, so we hash on the label value and
* the children's label values.
*
* @return The hash code
*/
@Override
public int hashCode() {
String v = this.value();
int hc = (v == null) ? 1 : v.hashCode();
Tree[] kids = children();
for (int i = 0; i < kids.length; i++) {
v = kids[i].value();
int hc2 = (v == null) ? i : v.hashCode();
hc ^= (hc2 << i);
}
return hc;
}
/**
* Returns the position of a Tree in the children list, if present,
* or -1 if it is not present. Trees are checked for presence with
* object equality, ==. Note that there are very few cases where an
* indexOf that used .equals() instead of == would be useful and
* correct. In most cases, you want to figure out which child of
* the parent a known tree is, so looking for object equality will
* be faster and will avoid cases where you happen to have two
* subtrees that are exactly the same.
*
* @param tree The tree to look for in children list
* @return Its index in the list or -1
*/
public int objectIndexOf(Tree tree) {
Tree[] kids = children();
for (int i = 0; i < kids.length; i++) {
if (kids[i] == tree) {
return i;
}
}
return -1;
}
/**
* Returns an array of children for the current node. If there
* are no children (if the node is a leaf), this must return a
* Tree[] array of length 0. A null children() value for tree
* leaves was previously supported, but no longer is.
* A caller may assume that either <code>isLeaf()</code> returns
* true, or this node has a nonzero number of children.
*
* @return The children of the node
* @see #getChildrenAsList()
*/
public abstract Tree[] children();
/**
* Returns a List of children for the current node. If there are no
* children, then a (non-null) <code>List<Tree></code> of size 0 will
* be returned. The list has new list structure but pointers to,
* not copies of the children. That is, the returned list is mutable,
* and simply adding to or deleting items from it is safe, but beware
* changing the contents of the children.
*
* @return The children of the node
*/
public List<Tree> getChildrenAsList() {
return new ArrayList<>(Arrays.asList(children()));
}
/**
* Set the children of this node to be the children given in the
* array. This is an <b>optional</b> operation; by default it is
* unsupported. Note for subclasses that if there are no
* children, the children() method must return a Tree[] array of
* length 0. This class provides a
* {@code EMPTY_TREE_ARRAY} canonical zero-length Tree[] array
* to represent zero children, but it is <i>not</i> required that
* leaf nodes use this particular zero-length array to represent
* a leaf node.
*
* @param children The array of children, each a <code>Tree</code>
* @see #setChildren(List)
*/
public void setChildren(Tree[] children) {
throw new UnsupportedOperationException();
}
/**
* Set the children of this tree node to the given list. This
* method is implemented in the <code>Tree</code> class by
* converting the <code>List</code> into a tree array and calling
* the array-based method. Subclasses which use a
* <code>List</code>-based representation of tree children should
* override this method. This implementation allows the case
* that the <code>List</code> is <code>null</code>: it yields a
* node with no children (represented by a canonical zero-length
* children() array).
*
* @param childTreesList A list of trees to become children of the node.
* This method does not retain the List that you pass it (copying
* is done), but it will retain the individual children (they are
* not copied).
* @see #setChildren(Tree[])
*/
public void setChildren(List<? extends Tree> childTreesList) {
if (childTreesList == null || childTreesList.isEmpty()) {
setChildren(EMPTY_TREE_ARRAY);
} else {
Tree[] childTrees = new Tree[childTreesList.size()];
childTreesList.toArray(childTrees);
setChildren(childTrees);
}
}
/**
* Returns the label associated with the current node, or null
* if there is no label. The default implementation always
* returns {@code null}.
*
* @return The label of the node
*/
@Override
public Label label() {
return null;
}
/**
* Sets the label associated with the current node, if there is one.
* The default implementation ignores the label.
*
* @param label The label
*/
@Override
public void setLabel(Label label) {
// a noop
}
/**
* Returns the score associated with the current node, or NaN
* if there is no score. The default implementation returns NaN.
*
* @return The score
*/
@Override
public double score() {
return Double.NaN;
}
/**
* Sets the score associated with the current node, if there is one.
*
* @param score The score
*/
public void setScore(double score) {
throw new UnsupportedOperationException("You must use a tree type that implements scoring in order call setScore()");
}
/**
* Returns the first child of a tree, or <code>null</code> if none.
*
* @return The first child
*/
public Tree firstChild() {
Tree[] kids = children();
if (kids.length == 0) {
return null;
}
return kids[0];
}
/**
* Returns the last child of a tree, or <code>null</code> if none.
*
* @return The last child
*/
public Tree lastChild() {
Tree[] kids = children();
if (kids.length == 0) {
return null;
}
return kids[kids.length - 1];
}
/** Return the highest node of the (perhaps trivial) unary chain that
* this node is part of.
* In case this node is the only child of its parent, trace up the chain of
* unaries, and return the uppermost node of the chain (the node whose
* parent has multiple children, or the node that is the root of the tree).
*
* @param root The root of the tree that contains this subtree
* @return The uppermost node of the unary chain, if this node is in a unary
* chain, or else the current node
*/
public Tree upperMostUnary(Tree root) {
Tree parent = parent(root);
if (parent == null) {
return this;
}
if (parent.numChildren() > 1) {
return this;
}
return parent.upperMostUnary(root);
}
/**
* Assign a SpanAnnotation on each node of this tree.
* The index starts at zero.
*/
public void setSpans() {
constituentsNodes(0);
}
/**
* Returns SpanAnnotation of this node, or null if annotation is not assigned.
* Use <code>setSpans()</code> to assign SpanAnnotations to a tree.
*
* @return an IntPair: the SpanAnnotation of this node.
*/
public IntPair getSpan() {
if(label() instanceof CoreMap && ((CoreMap) label()).containsKey(CoreAnnotations.SpanAnnotation.class))
return ((CoreMap) label()).get(CoreAnnotations.SpanAnnotation.class);
return null;
}
/**
* Returns the Constituents generated by the parse tree. Constituents
* are computed with respect to whitespace (e.g., at the word level).
*
* @return a Set of the constituents as constituents of
* type <code>Constituent</code>
*/
public Set<Constituent> constituents() {
return constituents(new SimpleConstituentFactory());
}
/**
* Returns the Constituents generated by the parse tree.
* The Constituents of a sentence include the preterminal categories
* but not the leaves.
*
* @param cf ConstituentFactory used to build the Constituent objects
* @return a Set of the constituents as SimpleConstituent type
* (in the current implementation, a <code>HashSet</code>
*/
public Set<Constituent> constituents(ConstituentFactory cf) {
return constituents(cf,false);
}
/**
* Returns the Constituents generated by the parse tree.
* The Constituents of a sentence include the preterminal categories
* but not the leaves.
*
* @param cf ConstituentFactory used to build the Constituent objects
* @param maxDepth The maximum depth at which to add constituents,
* where 0 is the root level. Negative maxDepth
* indicates no maximum.
* @return a Set of the constituents as SimpleConstituent type
* (in the current implementation, a <code>HashSet</code>
*/
public Set<Constituent> constituents(ConstituentFactory cf, int maxDepth) {
Set<Constituent> constituentsSet = Generics.newHashSet();
constituents(constituentsSet, 0, cf, false, null, maxDepth, 0);
return constituentsSet;
}
/**
* Returns the Constituents generated by the parse tree.
* The Constituents of a sentence include the preterminal categories
* but not the leaves.
*
* @param cf ConstituentFactory used to build the Constituent objects
* @param charLevel If true, compute bracketings irrespective of whitespace boundaries.
* @return a Set of the constituents as SimpleConstituent type
* (in the current implementation, a <code>HashSet</code>
*/
public Set<Constituent> constituents(ConstituentFactory cf, boolean charLevel) {
Set<Constituent> constituentsSet = Generics.newHashSet();
constituents(constituentsSet, 0, cf, charLevel, null, -1, 0);
return constituentsSet;
}
public Set<Constituent> constituents(ConstituentFactory cf, boolean charLevel, Predicate<Tree> filter) {
Set<Constituent> constituentsSet = Generics.newHashSet();
constituents(constituentsSet, 0, cf, charLevel, filter, -1, 0);
return constituentsSet;
}
/**
* Same as int constituents but just puts the span as an IntPair
* in the CoreLabel of the nodes.
*
* @param left The left position to begin labeling from
* @return The index of the right frontier of the constituent
*/
private int constituentsNodes(int left) {
if (isLeaf()) {
if (label() instanceof CoreLabel) {
((CoreLabel) label()).set(CoreAnnotations.SpanAnnotation.class, new IntPair(left, left));
} else {
throw new UnsupportedOperationException("Can only set spans on trees which use CoreLabel");
}
return (left + 1);
}
int position = left;
// enumerate through daughter trees
Tree[] kids = children();
for (Tree kid : kids)
position = kid.constituentsNodes(position);
//Parent span
if (label() instanceof CoreLabel) {
((CoreLabel) label()).set(CoreAnnotations.SpanAnnotation.class, new IntPair(left, position - 1));
} else {
throw new UnsupportedOperationException("Can only set spans on trees which use CoreLabel");
}
return position;
}
/**
* Adds the constituents derived from <code>this</code> tree to
* the ordered <code>Constituent</code> <code>Set</code>, beginning
* numbering from the second argument and returning the number of
* the right edge. The reason for the return of the right frontier
* is in order to produce bracketings recursively by threading through
* the daughters of a given tree.
*
* @param constituentsSet set of constituents to add results of bracketing
* this tree to
* @param left left position to begin labeling the bracketings with
* @param cf ConstituentFactory used to build the Constituent objects
* @param charLevel If true, compute constituents without respect to whitespace. Otherwise, preserve whitespace boundaries.
* @param filter A filter to use to decide whether or not to add a tree as a constituent.
* @param maxDepth The maximum depth at which to allow constituents. Set to negative to indicate all depths allowed.
* @param depth The current depth
* @return Index of right frontier of Constituent
*/
private int constituents(Set<Constituent> constituentsSet, int left, ConstituentFactory cf, boolean charLevel, Predicate<Tree> filter, int maxDepth, int depth) {
if(isPreTerminal())
return left + ((charLevel) ? firstChild().value().length() : 1);
int position = left;
// log.info("In bracketing trees left is " + left);
// log.info(" label is " + label() +
// "; num daughters: " + children().length);
Tree[] kids = children();
for (Tree kid : kids) {
position = kid.constituents(constituentsSet, position, cf, charLevel, filter, maxDepth, depth + 1);
// log.info(" position went to " + position);
}
if ((filter == null || filter.test(this)) &&
(maxDepth < 0 || depth <= maxDepth)) {
//Compute span of entire tree at the end of recursion
constituentsSet.add(cf.newConstituent(left, position - 1, label(), score()));
}
// log.info(" added " + label());
return position;
}
/**
* Returns a new Tree that represents the local Tree at a certain node.
* That is, it builds a new tree that copies the mother and daughter
* nodes (but not their Labels), as non-Leaf nodes,
* but zeroes out their children.
*
* @return A local tree
*/
public Tree localTree() {
Tree[] kids = children();
Tree[] newKids = new Tree[kids.length];
TreeFactory tf = treeFactory();
for (int i = 0, n = kids.length; i < n; i++) {
newKids[i] = tf.newTreeNode(kids[i].label(), Arrays.asList(EMPTY_TREE_ARRAY));
}
return tf.newTreeNode(label(), Arrays.asList(newKids));
}
/**
* Returns a set of one level <code>Tree</code>s that ares the local trees
* of the tree.
* That is, it builds a new tree that copies the mother and daughter
* nodes (but not their Labels), for each phrasal node,
* but zeroes out their children.
*
* @return A set of local tree
*/
public Set<Tree> localTrees() {
Set<Tree> set = Generics.newHashSet();
for (Tree st : this) {
if (st.isPhrasal()) {
set.add(st.localTree());
}
}
return set;
}
/**
* Most instances of <code>Tree</code> will take a lot more than
* than the default <code>StringBuffer</code> size of 16 to print
* as an indented list of the whole tree, so we enlarge the default.
*/
private static final int initialPrintStringBuilderSize = 500;
/**
* Appends the printed form of a parse tree (as a bracketed String)
* to a {@code StringBuilder}.
* The implementation of this may be more efficient than for
* {@code toString()} on complex trees.
*
* @param sb The {@code StringBuilder} to which the tree will be appended
* @return Returns the {@code StringBuilder} passed in with extra stuff in it
*/
public StringBuilder toStringBuilder(StringBuilder sb) {
return toStringBuilder(sb, true);
}
/**
* Appends the printed form of a parse tree (as a bracketed String)
* to a {@code StringBuilder}.
* The implementation of this may be more efficient than for
* {@code toString()} on complex trees.
*
* @param sb The {@code StringBuilder} to which the tree will be appended
* @param printOnlyLabelValue If true, print only the value() of each node's label
* @return Returns the {@code StringBuilder} passed in with extra stuff in it
*/
public StringBuilder toStringBuilder(StringBuilder sb, boolean printOnlyLabelValue) {
if (isLeaf()) {
if (label() != null) {
if(printOnlyLabelValue) {
sb.append(label().value());
} else {
sb.append(label());
}
}
return sb;
} else {
sb.append('(');
if (label() != null) {
if (printOnlyLabelValue) {
if (value() != null) {
sb.append(label().value());
}
// don't print a null, just nothing!
} else {
sb.append(label());
}
}
Tree[] kids = children();
if (kids != null) {
for (Tree kid : kids) {
sb.append(' ');
kid.toStringBuilder(sb, printOnlyLabelValue);
}
}
return sb.append(')');
}
}
/**
* Converts parse tree to string in Penn Treebank format.
* <p>
* Implementation note: Internally, the method gains
* efficiency by chaining use of a single <code>StringBuilder</code>
* through all the printing.
*
* @return the tree as a bracketed list on one line
*/
@Override
public String toString() {
return toStringBuilder(new StringBuilder(Tree.initialPrintStringBuilderSize)).toString();
}
private static final int indentIncr = 2;
private static String makeIndentString(int indent) {
StringBuilder sb = new StringBuilder(indent);
for (int i = 0; i < indentIncr; i++) {
sb.append(' ');
}
return sb.toString();
}
public void printLocalTree() {
printLocalTree(new PrintWriter(System.out, true));
}
/**
* Only prints the local tree structure, does not recurse
*/
public void printLocalTree(PrintWriter pw) {
pw.print("(" + label() + ' ');
for (Tree kid : children()) {
pw.print("(");
pw.print(kid.label());
pw.print(") ");
}
pw.println(")");
}
/**
* Indented list printing of a tree. The tree is printed in an
* indented list notation, with node labels followed by node scores.
*/
public void indentedListPrint() {
indentedListPrint(new PrintWriter(System.out, true), false);
}
/**
* Indented list printing of a tree. The tree is printed in an
* indented list notation, with node labels followed by node scores.
*
* @param pw The PrintWriter to print the tree to
* @param printScores Whether to print the scores (log probs) of tree nodes
*/
public void indentedListPrint(PrintWriter pw, boolean printScores) {
indentedListPrint("", makeIndentString(indentIncr), pw, printScores);
}
/**
* Indented list printing of a tree. The tree is printed in an
* indented list notation, with node labels followed by node scores.
* String parameters are used rather than integer levels for efficiency.
*
* @param indent The base <code>String</code> (normally just spaces)
* to print before each line of tree
* @param pad The additional <code>String</code> (normally just more
* spaces) to add when going to a deeper level of <code>Tree</code>.
* @param pw The PrintWriter to print the tree to
* @param printScores Whether to print the scores (log probs) of tree nodes
*/
private void indentedListPrint(String indent, String pad, PrintWriter pw, boolean printScores) {
StringBuilder sb = new StringBuilder(indent);
Label label = label();
if (label != null) {
sb.append(label.toString());
}
if (printScores) {
sb.append(" ");
sb.append(score());
}
pw.println(sb.toString());
Tree[] children = children();
String newIndent = indent + pad;
for (Tree child : children) {
child.indentedListPrint(newIndent, pad, pw, printScores);
}
}
/**
* Indented xml printing of a tree. The tree is printed in an
* indented xml notation.
*/
public void indentedXMLPrint() {
indentedXMLPrint(new PrintWriter(System.out, true), false);
}
/**
* Indented xml printing of a tree. The tree is printed in an
* indented xml notation, with node labels followed by node scores.
*
* @param pw The PrintWriter to print the tree to
* @param printScores Whether to print the scores (log probs) of tree nodes
*/
public void indentedXMLPrint(PrintWriter pw, boolean printScores) {
indentedXMLPrint("", makeIndentString(indentIncr), pw, printScores);
}
/**
* Indented xml printing of a tree. The tree is printed in an
* indented xml notation, with node labels followed by node scores.
* String parameters are used rather than integer levels for efficiency.
*
* @param indent The base <code>String</code> (normally just spaces)
* to print before each line of tree
* @param pad The additional <code>String</code> (normally just more
* spaces) to add when going to a deeper level of
* <code>Tree</code>.
* @param pw The PrintWriter to print the tree to
* @param printScores Whether to print the scores (log probs) of tree nodes
*/
private void indentedXMLPrint(String indent, String pad,
PrintWriter pw, boolean printScores) {
StringBuilder sb = new StringBuilder(indent);
Tree[] children = children();
Label label = label();
if (label != null) {
sb.append("<");
if (children.length > 0) {
sb.append("node value=\"");
} else {
sb.append("leaf value=\"");
}
sb.append(XMLUtils.escapeXML(SentenceUtils.wordToString(label, true)));
sb.append("\"");
if (printScores) {
sb.append(" score=");
sb.append(score());
}
if (children.length > 0) {
sb.append(">");
} else {
sb.append("/>");
}
} else {
if (children.length > 0) {
sb.append("<node>");
} else {
sb.append("<leaf/>");
}
}
pw.println(sb.toString());
if (children.length > 0) {
String newIndent = indent + pad;
for (Tree child : children) {
child.indentedXMLPrint(newIndent, pad, pw, printScores);
}
pw.println(indent + "</node>");
}
}
private static void displayChildren(Tree[] trChildren, int indent, boolean parentLabelNull, boolean onlyLabelValue, PrintWriter pw) {
boolean firstSibling = true;
boolean leftSibIsPreTerm = true; // counts as true at beginning
for (Tree currentTree : trChildren) {
currentTree.display(indent, parentLabelNull, firstSibling, leftSibIsPreTerm, false, onlyLabelValue, pw);
leftSibIsPreTerm = currentTree.isPreTerminal();
// CC is a special case for English, but leave it in so we can exactly match PTB3 tree formatting
if (currentTree.value() != null && currentTree.value().startsWith("CC")) {
leftSibIsPreTerm = false;
}
firstSibling = false;
}
}
/**
* Returns the value of the nodes label as a String. This is done by
* calling <code>toString()</code> on the value, if it exists. Otherwise,
* an empty string is returned.
*
* @return The label of a tree node as a String
*/
public String nodeString() {
return (value() == null) ? "" : value();
}
/**
* Display a node, implementing Penn Treebank style layout
*/
private void display(int indent, boolean parentLabelNull, boolean firstSibling, boolean leftSiblingPreTerminal, boolean topLevel, boolean onlyLabelValue, PrintWriter pw) {
// the condition for staying on the same line in Penn Treebank
boolean suppressIndent = (parentLabelNull || (firstSibling && isPreTerminal()) || (leftSiblingPreTerminal && isPreTerminal() && (label() == null || !label().value().startsWith("CC"))));
if (suppressIndent) {
pw.print(" ");
// pw.flush();
} else {
if (!topLevel) {
pw.println();
}
for (int i = 0; i < indent; i++) {
pw.print(" ");
// pw.flush();
}
}
if (isLeaf() || isPreTerminal()) {
String terminalString = toStringBuilder(new StringBuilder(), onlyLabelValue).toString();
pw.print(terminalString);
pw.flush();
return;
}
pw.print("(");
String nodeString;
if (onlyLabelValue) {
String value = value();
nodeString = (value == null) ? "" : value;
} else {
nodeString = nodeString();
}
pw.print(nodeString);
// pw.flush();
boolean parentIsNull = label() == null || label().value() == null;
displayChildren(children(), indent + 1, parentIsNull, true, pw);
pw.print(")");
pw.flush();
}
/**
* Print the tree as done in Penn Treebank merged files.
* The formatting should be exactly the same, but we don't print the
* trailing whitespace found in Penn Treebank trees.
* The basic deviation from a bracketed indented tree is to in general
* collapse the printing of adjacent preterminals onto one line of
* tags and words. Additional complexities are that conjunctions
* (tag CC) are not collapsed in this way, and that the unlabeled
* outer brackets are collapsed onto the same line as the next
* bracket down.
*
* @param pw The tree is printed to this <code>PrintWriter</code>
*/
public void pennPrint(PrintWriter pw) {
pennPrint(pw, true);
}
public void pennPrint(PrintWriter pw, boolean printOnlyLabelValue) {
display(0, false, false, false, true, printOnlyLabelValue, pw);
pw.println();
pw.flush();
}
/**
* Print the tree as done in Penn Treebank merged files.
* The formatting should be exactly the same, but we don't print the
* trailing whitespace found in Penn Treebank trees.
* The basic deviation from a bracketed indented tree is to in general
* collapse the printing of adjacent preterminals onto one line of
* tags and words. Additional complexities are that conjunctions
* (tag CC) are not collapsed in this way, and that the unlabeled
* outer brackets are collapsed onto the same line as the next
* bracket down.
*
* @param ps The tree is printed to this <code>PrintStream</code>
*/
public void pennPrint(PrintStream ps) {
pennPrint(new PrintWriter(new OutputStreamWriter(ps), true));
}
public void pennPrint(PrintStream ps, boolean printOnlyLabelValue) {
pennPrint(new PrintWriter(new OutputStreamWriter(ps), true), printOnlyLabelValue);
}
/**
* Calls <code>pennPrint()</code> and saves output to a String
*
* @return The indent S-expression representation of a Tree
*/
public String pennString() {
StringWriter sw = new StringWriter();
pennPrint(new PrintWriter(sw));
return sw.toString();
}
/**
* Print the tree as done in Penn Treebank merged files.
* The formatting should be exactly the same, but we don't print the
* trailing whitespace found in Penn Treebank trees.
* The tree is printed to <code>System.out</code>. The basic deviation
* from a bracketed indented tree is to in general
* collapse the printing of adjacent preterminals onto one line of
* tags and words. Additional complexities are that conjunctions
* (tag CC) are not collapsed in this way, and that the unlabeled
* outer brackets are collapsed onto the same line as the next
* bracket down.
*/
public void pennPrint() {
pennPrint(System.out);
}
/**
* Finds the depth of the tree. The depth is defined as the length
* of the longest path from this node to a leaf node. Leaf nodes
* have depth zero. POS tags have depth 1. Phrasal nodes have
* depth >= 2.
*
* @return the depth
*/
public int depth() {
if (isLeaf()) {
return 0;
}
int maxDepth = 0;
Tree[] kids = children();
for (Tree kid : kids) {
int curDepth = kid.depth();
if (curDepth > maxDepth) {
maxDepth = curDepth;
}
}
return maxDepth + 1;
}
/**
* Finds the distance from this node to the specified node.
* return -1 if this is not an ancestor of node.
*
* @param node A subtree contained in this tree
* @return the depth
*/
public int depth(Tree node) {
Tree p = node.parent(this);
if (this == node) { return 0; }
if (p == null) { return -1; }
int depth = 1;
while (this != p) {
p = p.parent(this);
depth++;
}
return depth;
}
/**
* Returns the tree leaf that is the head of the tree.
*
* @param hf The head-finding algorithm to use
* @param parent The parent of this tree
* @return The head tree leaf if any, else <code>null</code>
*/
public Tree headTerminal(HeadFinder hf, Tree parent) {
if (isLeaf()) {
return this;
}
Tree head = hf.determineHead(this, parent);
if (head != null) {
return head.headTerminal(hf, parent);
}
log.info("Head is null: " + this);
return null;
}
/**
* Returns the tree leaf that is the head of the tree.
*
* @param hf The headfinding algorithm to use
* @return The head tree leaf if any, else <code>null</code>
*/
public Tree headTerminal(HeadFinder hf) {
return headTerminal(hf, null);
}
/**
* Returns the preterminal tree that is the head of the tree.
* See {@link #isPreTerminal()} for
* the definition of a preterminal node. Beware that some tree nodes may
* have no preterminal head.
*
* @param hf The headfinding algorithm to use
* @return The head preterminal tree, if any, else <code>null</code>
* @throws IllegalArgumentException if called on a leaf node
*/
public Tree headPreTerminal(HeadFinder hf) {
if (isPreTerminal()) {
return this;
} else if (isLeaf()) {
throw new IllegalArgumentException("Called headPreTerminal on a leaf: " + this);
} else {
Tree head = hf.determineHead(this);
if (head != null) {
return head.headPreTerminal(hf);
}
log.info("Head preterminal is null: " + this);
return null;
}
}
/**
* Finds the head words of each tree and assigns
* HeadWordLabelAnnotation on each node pointing to the correct
* CoreLabel. This relies on the nodes being CoreLabels, so it
* throws an IllegalArgumentException if this is ever not true.
*/
public void percolateHeadAnnotations(HeadFinder hf) {
if (!(label() instanceof CoreLabel)) {
throw new IllegalArgumentException("Expected CoreLabels in the trees");
}
CoreLabel nodeLabel = (CoreLabel) label();
if (isLeaf()) {
return;
}
if (isPreTerminal()) {
nodeLabel.set(TreeCoreAnnotations.HeadWordLabelAnnotation.class, (CoreLabel) children()[0].label());
nodeLabel.set(TreeCoreAnnotations.HeadTagLabelAnnotation.class, nodeLabel);
return;
}
for (Tree kid : children()) {
kid.percolateHeadAnnotations(hf);
}
final Tree head = hf.determineHead(this);
if (head == null) {
throw new NullPointerException("HeadFinder " + hf + " returned null for " + this);
} else if (head.isLeaf()) {
nodeLabel.set(TreeCoreAnnotations.HeadWordLabelAnnotation.class, (CoreLabel) head.label());
nodeLabel.set(TreeCoreAnnotations.HeadTagLabelAnnotation.class, (CoreLabel) head.parent(this).label());
} else if (head.isPreTerminal()) {
nodeLabel.set(TreeCoreAnnotations.HeadWordLabelAnnotation.class, (CoreLabel) head.children()[0].label());
nodeLabel.set(TreeCoreAnnotations.HeadTagLabelAnnotation.class, (CoreLabel) head.label());
} else {
if (!(head.label() instanceof CoreLabel)) {
throw new AssertionError("Horrible bug");
}
CoreLabel headLabel = (CoreLabel) head.label();
nodeLabel.set(TreeCoreAnnotations.HeadWordLabelAnnotation.class, headLabel.get(TreeCoreAnnotations.HeadWordLabelAnnotation.class));
nodeLabel.set(TreeCoreAnnotations.HeadTagLabelAnnotation.class, headLabel.get(TreeCoreAnnotations.HeadTagLabelAnnotation.class));
}
}
/**
* Finds the heads of the tree. This code assumes that the label
* does store and return sensible values for the category, word, and tag.
* It will be a no-op otherwise. The tree is modified. The routine
* assumes the Tree has word leaves and tag preterminals, and copies
* their category to word and tag respectively, if they have a null
* value.
*
* @param hf The headfinding algorithm to use
*/
public void percolateHeads(HeadFinder hf) {
Label nodeLabel = label();
if (isLeaf()) {
// Sanity check: word() is usually set by the TreeReader.
if (nodeLabel instanceof HasWord) {
HasWord w = (HasWord) nodeLabel;
if (w.word() == null) {
w.setWord(nodeLabel.value());
}
}
} else {
for (Tree kid : children()) {
kid.percolateHeads(hf);
}
final Tree head = hf.determineHead(this);
if (head != null) {
final Label headLabel = head.label();
// Set the head tag.
String headTag = (headLabel instanceof HasTag) ? ((HasTag) headLabel).tag() : null;
if (headTag == null && head.isLeaf()) {
// below us is a leaf
headTag = nodeLabel.value();
}
// Set the head word
String headWord = (headLabel instanceof HasWord) ? ((HasWord) headLabel).word() : null;
if (headWord == null && head.isLeaf()) {
// below us is a leaf
// this might be useful despite case for leaf above in
// case the leaf label type doesn't support word()
headWord = headLabel.value();
}
// Set the head index
int headIndex = (headLabel instanceof HasIndex) ? ((HasIndex) headLabel).index() : -1;
if (nodeLabel instanceof HasWord) {
((HasWord) nodeLabel).setWord(headWord);
}
if (nodeLabel instanceof HasTag) {
((HasTag) nodeLabel).setTag(headTag);
}
if (nodeLabel instanceof HasIndex && headIndex >= 0) {
((HasIndex) nodeLabel).setIndex(headIndex);
}
} else {
log.info("Head is null: " + this);
}
}
}
/**
* Return a Set of TaggedWord-TaggedWord dependencies, represented as
* Dependency objects, for the Tree. This will only give
* useful results if the internal tree node labels support HasWord and
* HasTag, and head percolation has already been done (see
* percolateHeads()).
*
* @return Set of dependencies (each a Dependency)
*/
public Set<Dependency<Label, Label, Object>> dependencies() {
return dependencies(Filters.<Dependency<Label, Label, Object>>acceptFilter());
}
public Set<Dependency<Label, Label, Object>> dependencies(Predicate<Dependency<Label, Label, Object>> f) {
return dependencies(f, true, true, false);
}
/**
* Convert a constituency label to a dependency label. Options are provided for selecting annotations
* to copy.
*
* @param oldLabel
* @param copyLabel
* @param copyIndex
* @param copyPosTag
*/
private static Label makeDependencyLabel(Label oldLabel, boolean copyLabel, boolean copyIndex, boolean copyPosTag) {
if ( ! copyLabel)
return oldLabel;
String wordForm = (oldLabel instanceof HasWord) ? ((HasWord) oldLabel).word() : oldLabel.value();
Label newLabel = oldLabel.labelFactory().newLabel(wordForm);
if (newLabel instanceof HasWord) ((HasWord) newLabel).setWord(wordForm);
if (copyPosTag && newLabel instanceof HasTag && oldLabel instanceof HasTag) {
String tag = ((HasTag) oldLabel).tag();
((HasTag) newLabel).setTag(tag);
}
if (copyIndex && newLabel instanceof HasIndex && oldLabel instanceof HasIndex) {
int index = ((HasIndex) oldLabel).index();
((HasIndex) newLabel).setIndex(index);
}
return newLabel;
}
/**
* Return a set of TaggedWord-TaggedWord dependencies, represented as
* Dependency objects, for the Tree. This will only give
* useful results if the internal tree node labels support HasWord and
* head percolation has already been done (see percolateHeads()).
*
* @param f Dependencies are excluded for which the Dependency is not
* accepted by the Filter
* @return Set of dependencies (each a Dependency)
*/
public Set<Dependency<Label, Label, Object>> dependencies(Predicate<Dependency<Label, Label, Object>> f, boolean isConcrete, boolean copyLabel, boolean copyPosTag) {
Set<Dependency<Label, Label, Object>> deps = Generics.newHashSet();
for (Tree node : this) {
// Skip leaves and unary re-writes
if (node.isLeaf() || node.children().length < 2) {
continue;
}
// Create the head label (percolateHeads has already been executed)
Label headLabel = makeDependencyLabel(node.label(), copyLabel, isConcrete, copyPosTag);
String headWord = ((HasWord) headLabel).word();
if (headWord == null) {
headWord = headLabel.value();
}
int headIndex = (isConcrete && (headLabel instanceof HasIndex)) ? ((HasIndex) headLabel).index() : -1;
// every child with a different (or repeated) head is an argument
boolean seenHead = false;
for (Tree child : node.children()) {
Label depLabel = makeDependencyLabel(child.label(), copyLabel, isConcrete, copyPosTag);
String depWord = ((HasWord) depLabel).word();
if (depWord == null) {
depWord = depLabel.value();
}
int depIndex = (isConcrete && (depLabel instanceof HasIndex)) ? ((HasIndex) depLabel).index() : -1;
if (!seenHead && headIndex == depIndex && headWord.equals(depWord)) {
seenHead = true;
} else {
Dependency<Label, Label, Object> dependency = (isConcrete && depIndex != headIndex) ?
new UnnamedConcreteDependency(headLabel, depLabel) :
new UnnamedDependency(headLabel, depLabel);
if (f.test(dependency)) {
deps.add(dependency);
}
}
}
}
return deps;
}
/**
* Return a set of Label-Label dependencies, represented as
* Dependency objects, for the Tree. The Labels are the ones of the leaf
* nodes of the tree, without mucking with them.
*
* @param f Dependencies are excluded for which the Dependency is not
* accepted by the Filter
* @param hf The HeadFinder to use to identify the head of constituents.
* The code assumes
* that it can use <code>headPreTerminal(hf)</code> to find a
* tag and word to make a CoreLabel.
* @return Set of dependencies (each a <code>Dependency</code> between two
* <code>CoreLabel</code>s, which each contain a tag(), word(),
* and value(), the last two of which are identical).
*/
public Set<Dependency<Label, Label, Object>> mapDependencies(Predicate<Dependency<Label, Label, Object>> f, HeadFinder hf) {
if (hf == null) {
throw new IllegalArgumentException("mapDependencies: need HeadFinder");
}
Set<Dependency<Label, Label, Object>> deps = Generics.newHashSet();
for (Tree node : this) {
if (node.isLeaf() || node.children().length < 2) {
continue;
}
// Label l = node.label();
// log.info("doing kids of label: " + l);
//Tree hwt = node.headPreTerminal(hf);
Tree hwt = node.headTerminal(hf);
// log.info("have hf, found head preterm: " + hwt);
if (hwt == null) {
throw new IllegalStateException("mapDependencies: HeadFinder failed!");
}
for (Tree child : node.children()) {
// Label dl = child.label();
// Tree dwt = child.headPreTerminal(hf);
Tree dwt = child.headTerminal(hf);
if (dwt == null) {
throw new IllegalStateException("mapDependencies: HeadFinder failed!");
}
//log.info("kid is " + dl);
//log.info("transformed to " + dml.toString("value{map}"));
if (dwt != hwt) {
Dependency<Label, Label, Object> p = new UnnamedDependency(hwt.label(), dwt.label());
if (f.test(p)) {
deps.add(p);
}
}
}
}
return deps;
}
/**
* Return a set of Label-Label dependencies, represented as
* Dependency objects, for the Tree. The Labels are the ones of the leaf
* nodes of the tree, without mucking with them. The head of the sentence is a
* dependent of a synthetic "root" label.
*
* @param f Dependencies are excluded for which the Dependency is not
* accepted by the Filter
* @param hf The HeadFinder to use to identify the head of constituents.
* The code assumes
* that it can use <code>headPreTerminal(hf)</code> to find a
* tag and word to make a CoreLabel.
* @param rootName Name of the root node.
* @return Set of dependencies (each a <code>Dependency</code> between two
* <code>CoreLabel</code>s, which each contain a tag(), word(),
* and value(), the last two of which are identical).
*/
public Set<Dependency<Label, Label, Object>> mapDependencies(Predicate<Dependency<Label, Label, Object>> f, HeadFinder hf, String rootName) {
Set<Dependency<Label, Label, Object>> deps = mapDependencies(f, hf);
if(rootName != null) {
Label hl = headTerminal(hf).label();
CoreLabel rl = new CoreLabel();
rl.set(CoreAnnotations.TextAnnotation.class, rootName);
rl.set(CoreAnnotations.IndexAnnotation.class, 0);
deps.add(new NamedDependency(rl, hl, rootName));
}
return deps;
}
/**
* Gets the yield of the tree. The <code>Label</code> of all leaf nodes
* is returned
* as a list ordered by the natural left to right order of the
* leaves. Null values, if any, are inserted into the list like any
* other value.
*
* @return a <code>List</code> of the data in the tree's leaves.
*/
public ArrayList<Label> yield() {
return yield(new ArrayList<Label>());
}
/**
* Gets the yield of the tree. The <code>Label</code> of all leaf nodes
* is returned
* as a list ordered by the natural left to right order of the
* leaves. Null values, if any, are inserted into the list like any
* other value.
* <p><i>Implementation notes:</i> c. 2003: This has been rewritten to thread, so only one List
* is used. 2007: This method was duplicated to start to give type safety to Sentence.
* This method will now make a Word for any Leaf which does not itself implement HasWord, and
* put the Word into the Sentence, so the Sentence elements MUST implement HasWord.
*
* @param y The list in which the yield of the tree will be placed.
* Normally, this will be empty when the routine is called, but
* if not, the new yield is added to the end of the list.
* @return a <code>List</code> of the data in the tree's leaves.
*/
public ArrayList<Label> yield(ArrayList<Label> y) {
if (isLeaf()) {
y.add(label());
} else {
Tree[] kids = children();
for (Tree kid : kids) {
kid.yield(y);
}
}
return y;
}
public ArrayList<Word> yieldWords() {
return yieldWords(new ArrayList<>());
}
public ArrayList<Word> yieldWords(ArrayList<Word> y) {
if (isLeaf()) {
y.add(new Word(label()));
} else {
for (Tree kid : children()) {
kid.yieldWords(y);
}
}
return y;
}
public <X extends HasWord> ArrayList<X> yieldHasWord() {
return yieldHasWord(new ArrayList<>());
}
@SuppressWarnings("unchecked")
public <X extends HasWord> ArrayList<X> yieldHasWord(ArrayList<X> y) {
if (isLeaf()) {
Label lab = label();
// cdm: this is new hacked in stuff in Mar 2007 so we can now have a
// well-typed version of a Sentence, whose objects MUST implement HasWord
//
// wsg (Feb. 2010) - More hacks for trees with CoreLabels in which the type implements
// HasWord but only the value field is populated. This can happen if legacy code uses
// LabeledScoredTreeFactory but passes in a StringLabel to e.g. newLeaf().
if (lab instanceof HasWord) {
if(lab instanceof CoreLabel) {
CoreLabel cl = (CoreLabel) lab;
if(cl.word() == null)
cl.setWord(cl.value());
y.add((X) cl);
} else {
y.add((X) lab);
}
} else {
y.add((X) new Word(lab));
}
} else {
Tree[] kids = children();
for (Tree kid : kids) {
kid.yield(y);
}
}
return y;
}
/**
* Gets the yield of the tree. The <code>Label</code> of all leaf nodes
* is returned
* as a list ordered by the natural left to right order of the
* leaves. Null values, if any, are inserted into the list like any
* other value. This has been rewritten to thread, so only one List
* is used.
*
* @param y The list in which the yield of the tree will be placed.
* Normally, this will be empty when the routine is called, but
* if not, the new yield is added to the end of the list.
* @return a <code>List</code> of the data in the tree's leaves.
*/
@SuppressWarnings("unchecked")
public <T> List<T> yield(List<T> y) {
if (isLeaf()) {
if(label() instanceof HasWord) {
HasWord hw = (HasWord) label();
hw.setWord(label().value());
}
y.add((T) label());
} else {
Tree[] kids = children();
for (Tree kid : kids) {
kid.yield(y);
}
}
return y;
}
/**
* Gets the tagged yield of the tree.
* The <code>Label</code> of all leaf nodes is returned
* as a list ordered by the natural left to right order of the
* leaves. Null values, if any, are inserted into the list like any
* other value.
*
* @return a <code>List</code> of the data in the tree's leaves.
*/
public ArrayList<TaggedWord> taggedYield() {
return taggedYield(new ArrayList<>());
}
public List<LabeledWord> labeledYield() {
return labeledYield(new ArrayList<>());
}
/**
* Gets the tagged yield of the tree -- that is, get the preterminals
* as well as the terminals. The <code>Label</code> of all leaf nodes
* is returned
* as a list ordered by the natural left to right order of the
* leaves. Null values, if any, are inserted into the list like any
* other value. This has been rewritten to thread, so only one List
* is used.
* <p/>
* <i>Implementation note:</i> when we summon up enough courage, this
* method will be changed to take and return a {@code List<W extends TaggedWord>}.
*
* @param ty The list in which the tagged yield of the tree will be
* placed. Normally, this will be empty when the routine is called,
* but if not, the new yield is added to the end of the list.
* @return a <code>List</code> of the data in the tree's leaves.
*/
public <X extends List<TaggedWord>> X taggedYield(X ty) {
if (isPreTerminal()) {
ty.add(new TaggedWord(firstChild().label(), label()));
} else {
for (Tree kid : children()) {
kid.taggedYield(ty);
}
}
return ty;
}
public List<LabeledWord> labeledYield(List<LabeledWord> ty) {
if (isPreTerminal()) {
ty.add(new LabeledWord(firstChild().label(), label()));
} else {
for (Tree kid : children()) {
kid.labeledYield(ty);
}
}
return ty;
}
/** Returns a {@code List<CoreLabel>} from the tree.
* These are a copy of the complete token representation
* that adds the tag as the tag and value.
*
* @return A tagged, labeled yield.
*/
public List<CoreLabel> taggedLabeledYield() {
List<CoreLabel> ty = new ArrayList<>();
taggedLabeledYield(ty, 0);
return ty;
}
private int taggedLabeledYield(List<CoreLabel> ty, int termIdx) {
if (isPreTerminal()) {
// usually this will fill in all the usual keys for a token
CoreLabel taggedWord = new CoreLabel(firstChild().label());
// but in case this just came from reading a tree that just has a value for words
if (taggedWord.word() == null) {
taggedWord.setWord(firstChild().value());
}
final String tag = (value() == null) ? "" : value();
// set value and tag to the tag
taggedWord.setValue(tag);
taggedWord.setTag(tag);
taggedWord.setIndex(termIdx);
ty.add(taggedWord);
return termIdx + 1;
} else {
for (Tree kid : getChildrenAsList())
termIdx = kid.taggedLabeledYield(ty, termIdx);
}
return termIdx;
}
/**
* Gets the preterminal yield (i.e., tags) of the tree. All data in
* preterminal nodes is returned as a list ordered by the natural left to
* right order of the tree. Null values, if any, are inserted into the
* list like any other value. Pre-leaves are nodes of height 1.
*
* @return a {@code List} of the data in the tree's pre-leaves.
*/
public List<Label> preTerminalYield() {
return preTerminalYield(new ArrayList<>());
}
/**
* Gets the preterminal yield (i.e., tags) of the tree. All data in
* preleaf nodes is returned as a list ordered by the natural left to
* right order of the tree. Null values, if any, are inserted into the
* list like any other value. Pre-leaves are nodes of height 1.
*
* @param y The list in which the preterminals of the tree will be
* placed. Normally, this will be empty when the routine is called,
* but if not, the new yield is added to the end of the list.
* @return a <code>List</code> of the data in the tree's pre-leaves.
*/
public List<Label> preTerminalYield(List<Label> y) {
if (isPreTerminal()) {
y.add(label());
} else {
Tree[] kids = children();
for (Tree kid : kids) {
kid.preTerminalYield(y);
}
}
return y;
}
/**
* Gets the leaves of the tree. All leaves nodes are returned as a list
* ordered by the natural left to right order of the tree. Null values,
* if any, are inserted into the list like any other value.
*
* @return a <code>List</code> of the leaves.
*/
public <T extends Tree> List<T> getLeaves() {
return getLeaves(new ArrayList<>());
}
/**
* Gets the leaves of the tree.
*
* @param list The list in which the leaves of the tree will be
* placed. Normally, this will be empty when the routine is called,
* but if not, the new yield is added to the end of the list.
* @return a <code>List</code> of the leaves.
*/
@SuppressWarnings("unchecked")
public <T extends Tree> List<T> getLeaves(List<T> list) {
if (isLeaf()) {
list.add((T)this);
} else {
for (Tree kid : children()) {
kid.getLeaves(list);
}
}
return list;
}
/**
* Get the set of all node and leaf {@code Label}s,
* null or otherwise, contained in the tree.
*
* @return the {@code Collection} (actually, Set) of all values
* in the tree.
*/
@Override
public Collection<Label> labels() {
Set<Label> n = Generics.newHashSet();
n.add(label());
Tree[] kids = children();
for (Tree kid : kids) {
n.addAll(kid.labels());
}
return n;
}
@Override
public void setLabels(Collection<Label> c) {
throw new UnsupportedOperationException("Can't set Tree labels");
}
/**
* Return a flattened version of a tree. In many circumstances, this
* will just return the tree, but if the tree is something like a
* binarized version of a dependency grammar tree, then it will be
* flattened back to a dependency grammar tree representation. Formally,
* a node will be removed from the tree when: it is not a terminal or
* preterminal, and its <code>label()</code is <code>equal()</code> to
* the <code>label()</code> of its parent, and all its children will
* then be promoted to become children of the parent (in the same
* position in the sequence of daughters.
*
* @return A flattened version of this tree.
*/
public Tree flatten() {
return flatten(treeFactory());
}
/**
* Return a flattened version of a tree. In many circumstances, this
* will just return the tree, but if the tree is something like a
* binarized version of a dependency grammar tree, then it will be
* flattened back to a dependency grammar tree representation. Formally,
* a node will be removed from the tree when: it is not a terminal or
* preterminal, and its <code>label()</code is <code>equal()</code> to
* the <code>label()</code> of its parent, and all its children will
* then be promoted to become children of the parent (in the same
* position in the sequence of daughters. <p>
* Note: In the current implementation, the tree structure is mainly
* duplicated, but the links between preterminals and terminals aren't.
*
* @param tf TreeFactory used to create tree structure for flattened tree
* @return A flattened version of this tree.
*/
public Tree flatten(TreeFactory tf) {
if (isLeaf() || isPreTerminal()) {
return this;
}
Tree[] kids = children();
List<Tree> newChildren = new ArrayList<>(kids.length);
for (Tree child : kids) {
if (child.isLeaf() || child.isPreTerminal()) {
newChildren.add(child);
} else {
Tree newChild = child.flatten(tf);
if (label().equals(newChild.label())) {
newChildren.addAll(newChild.getChildrenAsList());
} else {
newChildren.add(newChild);
}
}
}
return tf.newTreeNode(label(), newChildren);
}
/**
* Get the set of all subtrees inside the tree by returning a tree
* rooted at each node. These are <i>not</i> copies, but all share
* structure. The tree is regarded as a subtree of itself.
* <p/>
* <i>Note:</i> If you only want to form this Set so that you can
* iterate over it, it is more efficient to simply use the Tree class's
* own <code>iterator() method. This will iterate over the exact same
* elements (but perhaps/probably in a different order).
*
* @return the <code>Set</code> of all subtrees in the tree.
*/
public Set<Tree> subTrees() {
return subTrees(Generics.<Tree>newHashSet());
}
/**
* Get the list of all subtrees inside the tree by returning a tree
* rooted at each node. These are <i>not</i> copies, but all share
* structure. The tree is regarded as a subtree of itself.
* <p/>
* <i>Note:</i> If you only want to form this Collection so that you can
* iterate over it, it is more efficient to simply use the Tree class's
* own <code>iterator() method. This will iterate over the exact same
* elements (but perhaps/probably in a different order).
*
* @return the <code>List</code> of all subtrees in the tree.
*/
public List<Tree> subTreeList() {
return subTrees(new ArrayList<>());
}
/**
* Add the set of all subtrees inside a tree (including the tree itself)
* to the given <code>Collection</code>.
* <p/>
* <i>Note:</i> If you only want to form this Collection so that you can
* iterate over it, it is more efficient to simply use the Tree class's
* own <code>iterator() method. This will iterate over the exact same
* elements (but perhaps/probably in a different order).
*
* @param n A collection of nodes to which the subtrees will be added.
* @return The collection parameter with the subtrees added.
*/
public <T extends Collection<Tree>> T subTrees(T n) {
n.add(this);
Tree[] kids = children();
for (Tree kid : kids) {
kid.subTrees(n);
}
return n;
}
/**
* Makes a deep copy of not only the Tree structure but of the labels as well.
* Uses the TreeFactory of the root node given by treeFactory().
* Assumes that your labels give a non-null labelFactory().
* (Added by Aria Haghighi.)
*
* @return A deep copy of the tree structure and its labels
*/
public Tree deepCopy() {
return deepCopy(treeFactory());
}
/**
* Makes a deep copy of not only the Tree structure but of the labels as well.
* The new tree will have nodes made by the given TreeFactory.
* Each Label is copied using the labelFactory() returned
* by the corresponding node's label.
* It assumes that your labels give non-null labelFactory.
* (Added by Aria Haghighi.)
*
* @param tf The TreeFactory used to make all nodes in the copied
* tree structure
* @return A Tree that is a deep copy of the tree structure and
* Labels of the original tree.
*/
public Tree deepCopy(TreeFactory tf) {
return deepCopy(tf, label().labelFactory());
}
/**
* Makes a deep copy of not only the Tree structure but of the labels as well.
* Each tree is copied with the given TreeFactory.
* Each Label is copied using the given LabelFactory.
* That is, the tree and label factories can transform the nature of the
* data representation.
*
* @param tf The TreeFactory used to make all nodes in the copied
* tree structure
* @param lf The LabelFactory used to make all nodes in the copied
* tree structure
* @return A Tree that is a deep copy of the tree structure and
* Labels of the original tree.
*/
@SuppressWarnings({"unchecked"})
public Tree deepCopy(TreeFactory tf, LabelFactory lf) {
Label label = lf.newLabel(label());
if (isLeaf()) {
return tf.newLeaf(label);
}
Tree[] kids = children();
// NB: The below list may not be of type Tree but TreeGraphNode, so we leave it untyped
List newKids = new ArrayList(kids.length);
for (Tree kid : kids) {
newKids.add(kid.deepCopy(tf, lf));
}
return tf.newTreeNode(label, newKids);
}
/**
* Create a deep copy of the tree structure. The entire structure is
* recursively copied, but label data themselves are not cloned.
* The copy is built using a <code>TreeFactory</code> that will
* produce a <code>Tree</code> like the input one.
*
* @return A deep copy of the tree structure (but not its labels).
*/
public Tree treeSkeletonCopy() {
return treeSkeletonCopy(treeFactory());
}
/**
* Create a deep copy of the tree structure. The entire structure is
* recursively copied, but label data themselves are not cloned.
* By specifying an appropriate <code>TreeFactory</code>, this
* method can be used to change the type of a <code>Tree</code>.
*
* @param tf The <code>TreeFactory</code> to be used for creating
* the returned <code>Tree</code>
* @return A deep copy of the tree structure (but not its labels).
*/
public Tree treeSkeletonCopy(TreeFactory tf) {
Tree t;
if (isLeaf()) {
t = tf.newLeaf(label());
} else {
Tree[] kids = children();
List<Tree> newKids = new ArrayList<>(kids.length);
for (Tree kid : kids) {
newKids.add(kid.treeSkeletonCopy(tf));
}
t = tf.newTreeNode(label(), newKids);
}
return t;
}
/**
* Returns a deep copy of everything but the leaf labels. The leaf
* labels are reused from the original tree. This is useful for
* cases such as the dependency converter, which wants to finish
* with the same labels in the dependencies as the parse tree.
*/
public Tree treeSkeletonConstituentCopy() {
return treeSkeletonConstituentCopy(treeFactory(), label().labelFactory());
}
public Tree treeSkeletonConstituentCopy(TreeFactory tf, LabelFactory lf) {
if (isLeaf()) {
// Reuse the current label for a leaf. This way, trees which
// are based on tokens in a sentence can have the same tokens
// even after a "deep copy".
// TODO: the LabeledScoredTreeFactory copies the label for a new
// leaf. Perhaps we could add a newLeafNoCopy or something like
// that for efficiency.
Tree newLeaf = tf.newLeaf(label());
newLeaf.setLabel(label());
return newLeaf;
}
Label label = lf.newLabel(label());
Tree[] kids = children();
List<Tree> newKids = new ArrayList<>(kids.length);
for (Tree kid : kids) {
newKids.add(kid.treeSkeletonConstituentCopy(tf, lf));
}
return tf.newTreeNode(label, newKids);
}
/**
* Create a transformed Tree. The tree is traversed in a depth-first,
* left-to-right order, and the <code>TreeTransformer</code> is called
* on each node. It returns some <code>Tree</code>. The transformed
* tree has a new tree structure (i.e., a "deep copy" is done), but it
* will usually share its labels with the original tree.
*
* @param transformer The function that transforms tree nodes or subtrees
* @return a transformation of this <code>Tree</code>
*/
public Tree transform(final TreeTransformer transformer) {
return transform(transformer, treeFactory());
}
/**
* Create a transformed Tree. The tree is traversed in a depth-first,
* left-to-right order, and the <code>TreeTransformer</code> is called
* on each node. It returns some <code>Tree</code>. The transformed
* tree has a new tree structure (i.e., a deep copy of the structure of the tree is done), but it
* will usually share its labels with the original tree.
*
* @param transformer The function that transforms tree nodes or subtrees
* @param tf The <code>TreeFactory</code> which will be used for creating
* new nodes for the returned <code>Tree</code>
* @return a transformation of this <code>Tree</code>
*/
public Tree transform(final TreeTransformer transformer, final TreeFactory tf) {
Tree t;
if (isLeaf()) {
t = tf.newLeaf(label());
} else {
Tree[] kids = children();
List<Tree> newKids = new ArrayList<>(kids.length);
for (Tree kid : kids) {
newKids.add(kid.transform(transformer, tf));
}
t = tf.newTreeNode(label(), newKids);
}
return transformer.transformTree(t);
}
/**
* Creates a (partial) deep copy of the tree, where all nodes that the
* filter does not accept are spliced out. If the result is not a tree
* (that is, it's a forest), an empty root node is generated.
*
* @param nodeFilter a Filter method which returns true to mean
* keep this node, false to mean delete it
* @return a filtered copy of the tree
*/
public Tree spliceOut(final Predicate<Tree> nodeFilter) {
return spliceOut(nodeFilter, treeFactory());
}
/**
* Creates a (partial) deep copy of the tree, where all nodes that the
* filter does not accept are spliced out. That is, the particular
* modes for which the <code>Filter</code> returns <code>false</code>
* are removed from the <code>Tree</code>, but those nodes' children
* are kept (assuming they pass the <code>Filter</code>, and they are
* added in the appropriate left-to-right ordering as new children of
* the parent node. If the root node is deleted, so that the result
* would not be a tree (that is, it's a forest), an empty root node is
* generated. If nothing is accepted, <code>null</code> is returned.
*
* @param nodeFilter a Filter method which returns true to mean
* keep this node, false to mean delete it
* @param tf A <code>TreeFactory</code> for making new trees. Used if
* the root node is deleted.
* @return a filtered copy of the tree.
*/
public Tree spliceOut(final Predicate<Tree> nodeFilter, final TreeFactory tf) {
List<Tree> l = spliceOutHelper(nodeFilter, tf);
if (l.isEmpty()) {
return null;
} else if (l.size() == 1) {
return l.get(0);
}
// for a forest, make a new root
return tf.newTreeNode((Label) null, l);
}
private List<Tree> spliceOutHelper(Predicate<Tree> nodeFilter, TreeFactory tf) {
// recurse over all children first
Tree[] kids = children();
List<Tree> l = new ArrayList<>();
for (Tree kid : kids) {
l.addAll(kid.spliceOutHelper(nodeFilter, tf));
}
// check if this node is being spliced out
if (nodeFilter.test(this)) {
// no, so add our children and return
Tree t;
if ( ! l.isEmpty()) {
t = tf.newTreeNode(label(), l);
} else {
t = tf.newLeaf(label());
}
l = new ArrayList<>(1);
l.add(t);
return l;
}
// we're out, so return our children
return l;
}
/**
* Creates a deep copy of the tree, where all nodes that the filter
* does not accept and all children of such nodes are pruned. If all
* of a node's children are pruned, that node is cut as well.
* A <code>Filter</code> can assume
* that it will not be called with a <code>null</code> argument.
* <p/>
* For example, the following code excises all PP nodes from a Tree: <br>
* <tt>
* Filter<Tree> f = new Filter<Tree> { <br>
* public boolean accept(Tree t) { <br>
* return ! t.label().value().equals("PP"); <br>
* } <br>
* }; <br>
* tree.prune(f);
* </tt> <br>
*
* If the root of the tree is pruned, null will be returned.
*
* @param filter the filter to be applied
* @return a filtered copy of the tree, including the possibility of
* <code>null</code> if the root node of the tree is filtered
*/
public Tree prune(final Predicate<Tree> filter) {
return prune(filter, treeFactory());
}
/**
* Creates a deep copy of the tree, where all nodes that the filter
* does not accept and all children of such nodes are pruned. If all
* of a node's children are pruned, that node is cut as well.
* A <code>Filter</code> can assume
* that it will not be called with a <code>null</code> argument.
*
* @param filter the filter to be applied
* @param tf the TreeFactory to be used to make new Tree nodes if needed
* @return a filtered copy of the tree, including the possibility of
* <code>null</code> if the root node of the tree is filtered
*/
public Tree prune(Predicate<Tree> filter, TreeFactory tf) {
// is the current node to be pruned?
if ( ! filter.test(this)) {
return null;
}
// if not, recurse over all children
List<Tree> l = new ArrayList<>();
Tree[] kids = children();
for (Tree kid : kids) {
Tree prunedChild = kid.prune(filter, tf);
if (prunedChild != null) {
l.add(prunedChild);
}
}
// and check if this node has lost all its children
if (l.isEmpty() && !(kids.length == 0)) {
return null;
}
// if we're still ok, copy the node
if (isLeaf()) {
return tf.newLeaf(label());
}
return tf.newTreeNode(label(), l);
}
/**
* Returns first child if this is unary and if the label at the current
* node is either "ROOT" or empty.
*
* @return The first child if this is unary and if the label at the current
* node is either "ROOT" or empty, else this
*/
public Tree skipRoot() {
if(!isUnaryRewrite())
return this;
String lab = label().value();
return (lab == null || lab.isEmpty() || "ROOT".equals(lab)) ? firstChild() : this;
}
/**
* Return a <code>TreeFactory</code> that produces trees of the
* appropriate type.
*
* @return A factory to produce Trees
*/
public abstract TreeFactory treeFactory();
/**
* Return the parent of the tree node. This routine may return
* <code>null</code> meaning simply that the implementation doesn't
* know how to determine the parent node, rather than there is no
* such node.
*
* @return The parent <code>Tree</code> node or <code>null</code>
* @see Tree#parent(Tree)
*/
public Tree parent() {
throw new UnsupportedOperationException();
}
/**
* Return the parent of the tree node. This routine will traverse
* a tree (depth first) from the given <code>root</code>, and will
* correctly find the parent, regardless of whether the concrete
* class stores parents. It will only return <code>null</code> if this
* node is the <code>root</code> node, or if this node is not
* contained within the tree rooted at <code>root</code>.
*
* @param root The root node of the whole Tree
* @return the parent <code>Tree</code> node if any;
* else <code>null</code>
*/
public Tree parent(Tree root) {
Tree[] kids = root.children();
return parentHelper(root, kids, this);
}
private static Tree parentHelper(Tree parent, Tree[] kids, Tree node) {
for (Tree kid : kids) {
if (kid == node) {
return parent;
}
Tree ret = node.parent(kid);
if (ret != null) {
return ret;
}
}
return null;
}
/**
* Returns the number of nodes the tree contains. This method
* implements the <code>size()</code> function required by the
* <code>Collections</code> interface. The size of the tree is the
* number of nodes it contains (of all types, including the leaf nodes
* and the root).
*
* @return The size of the tree
* @see #depth()
*/
@Override
public int size() {
int size = 1;
Tree[] kids = children();
for (Tree kid : kids) {
size += kid.size();
}
return size;
}
/**
* Return the ancestor tree node <code>height</code> nodes up from the current node.
*
* @param height How many nodes up to go. A parameter of 0 means return
* this node, 1 means to return the parent node and so on.
* @param root The root node that this Tree is embedded under
* @return The ancestor at height <code>height</code>. It returns null
* if it does not exist or the tree implementation does not keep track
* of parents
*/
public Tree ancestor(int height, Tree root) {
if (height < 0) {
throw new IllegalArgumentException("ancestor: height cannot be negative");
}
if (height == 0) {
return this;
}
Tree par = parent(root);
if (par == null) {
return null;
}
return par.ancestor(height - 1, root);
}
private static class TreeIterator implements Iterator<Tree> {
private final List<Tree> treeStack;
protected TreeIterator(Tree t) {
treeStack = new ArrayList<>();
treeStack.add(t);
}
@Override
public boolean hasNext() {
return (!treeStack.isEmpty());
}
@Override
public Tree next() {
int lastIndex = treeStack.size() - 1;
if (lastIndex < 0) {
throw new NoSuchElementException("TreeIterator exhausted");
}
Tree tr = treeStack.remove(lastIndex);
Tree[] kids = tr.children();
// so that we can efficiently use one List, we reverse them
for (int i = kids.length - 1; i >= 0; i--) {
treeStack.add(kids[i]);
}
return tr;
}
/**
* Not supported
*/
@Override
public void remove() {
throw new UnsupportedOperationException();
}
@Override
public String toString() {
return "TreeIterator";
}
}
/**
* Returns an iterator over all the nodes of the tree. This method
* implements the <code>iterator()</code> method required by the
* <code>Collections</code> interface. It does a preorder
* (children after node) traversal of the tree. (A possible
* extension to the class at some point would be to allow different
* traversal orderings via variant iterators.)
*
* @return An iterator over the nodes of the tree
*/
@Override
public Iterator<Tree> iterator() {
return new TreeIterator(this);
}
public List<Tree> postOrderNodeList() {
List<Tree> nodes = new ArrayList<>();
postOrderRecurse(this, nodes);
return nodes;
}
private static void postOrderRecurse(Tree t, List<Tree> nodes) {
for (Tree c : t.children()) {
postOrderRecurse(c, nodes);
}
nodes.add(t);
}
public List<Tree> preOrderNodeList() {
List<Tree> nodes = new ArrayList<>();
preOrderRecurse(this, nodes);
return nodes;
}
private static void preOrderRecurse(Tree t, List<Tree> nodes) {
nodes.add(t);
for (Tree c : t.children()) {
preOrderRecurse(c, nodes);
}
}
/**
* This gives you a tree from a String representation (as a
* bracketed Tree, of the kind produced by <code>toString()</code>,
* <code>pennPrint()</code>, or as in the Penn Treebank).
* It's not the most efficient thing to do for heavy duty usage.
* The Tree returned is created by a
* LabeledScoredTreeReaderFactory. This means that "standard"
* normalizations (stripping functional categories, indices,
* empty nodes, and A-over-A nodes) will be done on it.
*
* @param str The tree as a bracketed list in a String.
* @return The Tree
* @throws RuntimeException If Tree format is not valid
*/
public static Tree valueOf(String str) {
return valueOf(str, new LabeledScoredTreeReaderFactory());
}
/**
* This gives you a tree from a String representation (as a
* bracketed Tree, of the kind produced by <code>toString()</code>,
* <code>pennPrint()</code>, or as in the Penn Treebank.
* It's not the most efficient thing to do for heavy duty usage.
*
* @param str The tree as a bracketed list in a String.
* @param trf The TreeFactory used to make the new Tree
* @return The Tree
* @throws RuntimeException If the Tree format is not valid
*/
public static Tree valueOf(String str, TreeReaderFactory trf) {
try {
return trf.newTreeReader(new StringReader(str)).readTree();
} catch (IOException ioe) {
throw new RuntimeException("Tree.valueOf() tree construction failed", ioe);
}
}
/**
* Return the child at some daughter index. The children are numbered
* starting with an index of 0.
*
* @param i The daughter index
* @return The tree at that daughter index
*/
public Tree getChild(int i) {
Tree[] kids = children();
return kids[i];
}
/**
* Destructively removes the child at some daughter index and returns it.
* Note
* that this method will throw an {@link ArrayIndexOutOfBoundsException} if
* the daughter index is too big for the list of daughters.
*
* @param i The daughter index
* @return The tree at that daughter index
*/
public Tree removeChild(int i) {
Tree[] kids = children();
Tree kid = kids[i];
Tree[] newKids = new Tree[kids.length - 1];
for (int j = 0; j < newKids.length; j++) {
if (j < i) {
newKids[j] = kids[j];
} else {
newKids[j] = kids[j + 1];
}
}
setChildren(newKids);
return kid;
}
/**
* Adds the tree t at the index position among the daughters. Note
* that this method will throw an {@link ArrayIndexOutOfBoundsException} if
* the daughter index is too big for the list of daughters.
*
* @param i the index position at which to add the new daughter
* @param t the new daughter
*/
public void addChild(int i, Tree t) {
Tree[] kids = children();
Tree[] newKids = new Tree[kids.length + 1];
if (i != 0) {
System.arraycopy(kids, 0, newKids, 0, i);
}
newKids[i] = t;
if (i != kids.length) {
System.arraycopy(kids, i, newKids, i + 1, kids.length - i);
}
setChildren(newKids);
}
/**
* Adds the tree t at the last index position among the daughters.
*
* @param t the new daughter
*/
public void addChild(Tree t) {
addChild(children().length, t);
}
/**
* Replaces the <code>i</code>th child of <code>this</code> with the tree t.
* Note
* that this method will throw an {@link ArrayIndexOutOfBoundsException} if
* the child index is too big for the list of children.
*
* @param i The index position at which to replace the child
* @param t The new child
* @return The tree that was previously the ith d
*/
public Tree setChild(int i, Tree t) {
Tree[] kids = children();
Tree old = kids[i];
kids[i] = t;
return old;
}
/**
* Returns true if <code>this</code> dominates the Tree passed in
* as an argument. Object equality (==) rather than .equals() is used
* to determine domination.
* t.dominates(t) returns false.
*/
public boolean dominates(Tree t) {
List<Tree> dominationPath = dominationPath(t);
return dominationPath != null && dominationPath.size() > 1;
}
/**
* Returns the path of nodes leading down to a dominated node,
* including <code>this</code> and the dominated node itself.
* Returns null if t is not dominated by <code>this</code>. Object
* equality (==) is the relevant criterion.
* t.dominationPath(t) returns null.
*/
public List<Tree> dominationPath(Tree t) {
//Tree[] result = dominationPathHelper(t, 0);
Tree[] result = dominationPath(t, 0);
if (result == null) {
return null;
}
return Arrays.asList(result);
}
private Tree[] dominationPathHelper(Tree t, int depth) {
Tree[] kids = children();
for (int i = kids.length - 1; i >= 0; i--) {
Tree t1 = kids[i];
if (t1 == null) {
return null;
}
Tree[] result;
if ((result = t1.dominationPath(t, depth + 1)) != null) {
result[depth] = this;
return result;
}
}
return null;
}
private Tree[] dominationPath(Tree t, int depth) {
if (this == t) {
Tree[] result = new Tree[depth + 1];
result[depth] = this;
return result;
}
return dominationPathHelper(t, depth);
}
/**
* Given nodes <code>t1</code> and <code>t2</code> which are
* dominated by this node, returns a list of all the nodes on the
* path from t1 to t2, inclusive, or null if none found.
*/
public List<Tree> pathNodeToNode(Tree t1, Tree t2) {
if (!contains(t1) || !contains(t2)) {
return null;
}
if (t1 == t2) {
return Collections.singletonList(t1);
}
if (t1.dominates(t2)) {
return t1.dominationPath(t2);
}
if (t2.dominates(t1)) {
List<Tree> path = t2.dominationPath(t1);
Collections.reverse(path);
return path;
}
Tree joinNode = joinNode(t1, t2);
if (joinNode == null) {
return null;
}
List<Tree> t1DomPath = joinNode.dominationPath(t1);
List<Tree> t2DomPath = joinNode.dominationPath(t2);
if (t1DomPath == null || t2DomPath == null) {
return null;
}
ArrayList<Tree> path = new ArrayList<>();
path.addAll(t1DomPath);
Collections.reverse(path);
path.remove(joinNode);
path.addAll(t2DomPath);
return path;
}
/**
* Given nodes <code>t1</code> and <code>t2</code> which are
* dominated by this node, returns their "join node": the node
* <code>j</code> such that <code>j</code> dominates both
* <code>t1</code> and <code>t2</code>, and every other node which
* dominates both <code>t1</code> and <code>t2</code>
* dominates <code>j</code>.
* In the special case that t1 dominates t2, return t1, and vice versa.
* Return <code>null</code> if no such node can be found.
*/
public Tree joinNode(Tree t1, Tree t2) {
if (!contains(t1) || !contains(t2)) {
return null;
}
if (this == t1 || this == t2) {
return this;
}
Tree joinNode = null;
List<Tree> t1DomPath = dominationPath(t1);
List<Tree> t2DomPath = dominationPath(t2);
if (t1DomPath == null || t2DomPath == null) {
return null;
}
Iterator<Tree> it1 = t1DomPath.iterator();
Iterator<Tree> it2 = t2DomPath.iterator();
while (it1.hasNext() && it2.hasNext()) {
Tree n1 = it1.next();
Tree n2 = it2.next();
if (n1 != n2) {
break;
}
joinNode = n1;
}
return joinNode;
}
/**
* Given nodes {@code t1} and {@code t2} which are
* dominated by this node, returns {@code true} iff
* {@code t1} c-commands {@code t2}. (A node c-commands
* its sister(s) and any nodes below its sister(s).)
*/
public boolean cCommands(Tree t1, Tree t2) {
List<Tree> sibs = t1.siblings(this);
if (sibs == null) {
return false;
}
for (Tree sib : sibs) {
if (sib == t2 || sib.contains(t2)) {
return true;
}
}
return false;
}
/**
* Returns the siblings of this Tree node. The siblings are all
* children of the parent of this node except this node.
*
* @param root The root within which this tree node is contained
* @return The siblings as a list, an empty list if there are no siblings.
* The returned list is a modifiable new list structure, but contains
* the actual children.
*/
public List<Tree> siblings(Tree root) {
Tree parent = parent(root);
if (parent == null) {
return null;
}
List<Tree> siblings = parent.getChildrenAsList();
siblings.remove(this);
return siblings;
}
/**
* insert <code>dtr</code> after <code>position</code> existing
* daughters in <code>this</code>.
*/
public void insertDtr(Tree dtr, int position) {
Tree[] kids = children();
if (position > kids.length) {
throw new IllegalArgumentException("Can't insert tree after the " + position + "th daughter in " + this + "; only " + kids.length + " daughters exist!");
}
Tree[] newKids = new Tree[kids.length + 1];
int i = 0;
for (; i < position; i++) {
newKids[i] = kids[i];
}
newKids[i] = dtr;
for (; i < kids.length; i++) {
newKids[i + 1] = kids[i];
}
setChildren(newKids);
}
// --- composition methods to implement Label interface
@Override
public String value() {
Label lab = label();
if (lab == null) {
return null;
}
return lab.value();
}
@Override
public void setValue(String value) {
Label lab = label();
if (lab != null) {
lab.setValue(value);
}
}
@Override
public void setFromString(String labelStr) {
Label lab = label();
if (lab != null) {
lab.setFromString(labelStr);
}
}
/**
* Returns a factory that makes labels of the same type as this one.
* May return <code>null</code> if no appropriate factory is known.
*
* @return the LabelFactory for this kind of label
*/
@Override
public LabelFactory labelFactory() {
Label lab = label();
if (lab == null) {
return null;
}
return lab.labelFactory();
}
/**
* Returns the positional index of the left edge of <i>node</i> within the tree,
* as measured by characters. Returns -1 if <i>node is not found.</i>
* Note: These methods were written for internal evaluation routines. They are
* not the right methods to relate tree nodes to textual offsets. For these,
* look at the appropriate annotations on a CoreLabel (CharacterOffsetBeginAnnotation, etc.).
*/
public int leftCharEdge(Tree node) {
MutableInteger i = new MutableInteger(0);
if (leftCharEdge(node, i)) {
return i.intValue();
}
return -1;
}
private boolean leftCharEdge(Tree node, MutableInteger i) {
if (this == node) {
return true;
} else if (isLeaf()) {
i.set(i.intValue() + value().length());
return false;
} else {
for (Tree child : children()) {
if (child.leftCharEdge(node, i)) {
return true;
}
}
return false;
}
}
/**
* Returns the positional index of the right edge of <i>node</i> within the tree,
* as measured by characters. Returns -1 if <i>node is not found.</i>
*
* rightCharEdge returns the index of the rightmost character + 1, so that
* rightCharEdge(getLeaves().get(i)) == leftCharEdge(getLeaves().get(i+1))
*
* Note: These methods were written for internal evaluation routines. They are
* not the right methods to relate tree nodes to textual offsets. For these,
* look at the appropriate annotations on a CoreLabel (CharacterOffsetBeginAnnotation, etc.).
*
* @param node The subtree to look for in this Tree
* @return The positional index of the right edge of node
*/
public int rightCharEdge(Tree node) {
List<Tree> s = getLeaves();
int length = 0;
for (Tree leaf : s) {
length += leaf.label().value().length();
}
MutableInteger i = new MutableInteger(length);
if (rightCharEdge(node, i)) {
return i.intValue();
}
return -1;
}
private boolean rightCharEdge(Tree node, MutableInteger i) {
if (this == node) {
return true;
} else if (isLeaf()) {
i.set(i.intValue() - label().value().length());
return false;
} else {
for (int j = children().length - 1; j >= 0; j--) {
if (children()[j].rightCharEdge(node, i)) {
return true;
}
}
return false;
}
}
/**
* Calculates the node's <i>number</i>, defined as the number of nodes traversed in a left-to-right, depth-first search of the
* tree starting at <code>root</code> and ending at <code>this</code>. Returns -1 if <code>root</code> does not contain <code>this</code>.
* @param root the root node of the relevant tree
* @return the number of the current node, or -1 if <code>root</code> does not contain <code>this</code>.
*/
public int nodeNumber(Tree root) {
MutableInteger i = new MutableInteger(1);
if(nodeNumberHelper(root,i))
return i.intValue();
return -1;
}
private boolean nodeNumberHelper(Tree t, MutableInteger i) {
if(this==t)
return true;
i.incValue(1);
for (int j = 0; j < t.children().length; j++) {
if (nodeNumberHelper(t.children()[j],i))
return true;
}
return false;
}
/**
* Fetches the <code>i</code>th node in the tree, with node numbers defined
* as in {@link #nodeNumber(Tree)}.
*
* @param i the node number to fetch
* @return the <code>i</code>th node in the tree
* @throws IndexOutOfBoundsException if <code>i</code> is not between 1 and
* the number of nodes (inclusive) contained in <code>this</code>.
*/
public Tree getNodeNumber(int i) {
return getNodeNumberHelper(new MutableInteger(1),i);
}
private Tree getNodeNumberHelper(MutableInteger i, int target) {
int i1 = i.intValue();
if(i1 == target)
return this;
if(i1 > target)
throw new IndexOutOfBoundsException("Error -- tree does not contain " + i + " nodes.");
i.incValue(1);
for(int j = 0; j < children().length; j++) {
Tree temp = children()[j].getNodeNumberHelper(i, target);
if(temp != null)
return temp;
}
return null;
}
/**
* Assign sequential integer indices to the leaves of the tree
* rooted at this <code>Tree</code>, starting with 1.
* The leaves are traversed from left
* to right. If the node is already indexed, then it uses the existing index.
* This will only work if the leaves extend CoreMap.
*/
public void indexLeaves() {
indexLeaves(1, false);
}
/**
* Index the leaves, and optionally overwrite existing IndexAnnotations if they exist.
*
* @param overWrite Whether to replace an existing index for a leaf.
*/
public void indexLeaves(boolean overWrite) {
indexLeaves(1, overWrite);
}
/**
* Assign sequential integer indices to the leaves of the subtree
* rooted at this <code>Tree</code>, beginning with
* <code>startIndex</code>, and traversing the leaves from left
* to right. If node is already indexed, then it uses the existing index.
* This method only works if the labels of the tree implement
* CoreLabel!
*
* @param startIndex index for this node
* @param overWrite Whether to replace an existing index for a leaf.
* @return the next index still unassigned
*/
public int indexLeaves(int startIndex, boolean overWrite) {
if (isLeaf()) {
/*CoreLabel afl = (CoreLabel) label();
Integer oldIndex = afl.get(CoreAnnotations.IndexAnnotation.class);
if (!overWrite && oldIndex != null && oldIndex >= 0) {
startIndex = oldIndex;
} else {
afl.set(CoreAnnotations.IndexAnnotation.class, startIndex);
}*/
if(label() instanceof HasIndex) {
HasIndex hi = (HasIndex) label();
int oldIndex = hi.index();
if (!overWrite && oldIndex >= 0) {
startIndex = oldIndex;
} else {
hi.setIndex(startIndex);
}
startIndex++;
}
} else {
for (Tree kid : children()) {
startIndex = kid.indexLeaves(startIndex, overWrite);
}
}
return startIndex;
}
/**
* Percolates terminal indices through a dependency tree. The terminals should be indexed, e.g.,
* by calling indexLeaves() on the tree.
* <p>
* This method assumes CoreLabels!
*/
public void percolateHeadIndices() {
if (isPreTerminal()) {
int nodeIndex = ((HasIndex) firstChild().label()).index();
((HasIndex) label()).setIndex(nodeIndex);
return;
}
// Assign the head index to the first child that we encounter with a matching
// surface form. Obviously a head can have the same surface form as its dependent,
// and in this case the head index is ambiguous.
String wordAnnotation = ((HasWord) label()).word();
if (wordAnnotation == null) {
wordAnnotation = value();
}
boolean seenHead = false;
for (Tree child : children()) {
child.percolateHeadIndices();
String childWordAnnotation = ((HasWord) child.label()).word();
if (childWordAnnotation == null) {
childWordAnnotation = child.value();
}
if ( !seenHead && wordAnnotation.equals(childWordAnnotation)) {
seenHead = true;
int nodeIndex = ((HasIndex) child.label()).index();
((HasIndex) label()).setIndex(nodeIndex);
}
}
}
/** Index all spans (constituents) in the tree.
* For this, spans uses 0-based indexing and the span records the fencepost
* to the left of the first word and after the last word of the span.
* The spans are only recorded if the Tree has labels of a class which
* extends CoreMap.
*/
public void indexSpans() {
indexSpans(0);
}
public void indexSpans(int startIndex) {
indexSpans(new MutableInteger(startIndex));
}
/**
* Assigns span indices (BeginIndexAnnotation and EndIndexAnnotation) to all nodes in a tree.
* The beginning index is equivalent to the IndexAnnotation of the first leaf in the constituent.
* The end index is equivalent to the first integer after the IndexAnnotation of the last leaf in the constituent.
*
* @param startIndex Begin indexing at this value
*/
public Pair<Integer, Integer> indexSpans(MutableInteger startIndex) {
int start = Integer.MAX_VALUE;
int end = Integer.MIN_VALUE;
if(isLeaf()){
start = startIndex.intValue();
end = startIndex.intValue() + 1;
startIndex.incValue(1);
} else {
for (Tree kid : children()) {
Pair<Integer, Integer> span = kid.indexSpans(startIndex);
if(span.first < start) start = span.first;
if(span.second > end) end = span.second;
}
}
Label label = label();
if (label instanceof CoreMap) {
CoreMap afl = (CoreMap) label();
afl.set(CoreAnnotations.BeginIndexAnnotation.class, start);
afl.set(CoreAnnotations.EndIndexAnnotation.class, end);
}
return new Pair<>(start, end);
}
}